Humidity Level - HP Integrity rx5670 Site Preparation Manual

General Site Preparation Guidelines
Environmental Elements
• Underfloor air distribution system—Downflow air conditioning equipment located on the raised floor of
the computer room uses the cavity beneath the raised floor as a plenum for the supply air.
Return air from an underfloor air distribution system can be ducted return air (DRA) above the ceiling.
Perforated floor panels (available from the raised floor manufacturer) should be located around the front
of the system cabinets. Supply air emitted though the perforated floor panels is then available near the
cooling air intake vents of the hp Integrity rx5670 cabinets.
• Ceiling plenum air distribution system—Supply air is ducted into the ceiling plenum from upflow air
conditioning equipment located in the computer room or from an air handling unit (remote).
The ceiling construction should resist air leakage. Place perforated ceiling panels (with down discharge
air flow characteristics) around the front of the system cabinets. The supply air emitted downward from
the perforated ceiling panels is then available near the cooling air intake vents of the hp Integrity rx5670
cabinets.
Return air should be ducted back to the air conditioning equipment though the return air duct above the
ceiling.
• Above ceiling ducted air distribution system—Supply air is ducted into a ceiling diffuser system from
upflow air conditioning equipment located in the computer room or from an air handling unit (remote).
Return air from an above ceiling ducted air distribution system may be ducted return air (DRA) above the
ceiling, or ceiling plenum return air (CPRA).
Adjust the supply air diffuser system grilles to direct the cooling air downward around the front of the hp
Integrity rx5670 cabinets. The supply air is then available near the cooling air intake vents of the hp
Integrity rx5670 cabinets.
Air Conditioning System Installation
All air conditioning equipment, materials, and installation must comply with any applicable construction
codes. Installation of the various components of the air conditioning system must also conform to the air
conditioning equipment manufacturer's recommendations.
Air Conditioning Ducts
Use separate computer room air conditioning duct work. If it is not separate from the rest of the building, it
might be difficult to control cooling and air pressure levels. Duct work seals are important for maintaining a
balanced air conditioning system and high static air pressure. Adequate cooling capacity means little if the
direction and rate of air flow cannot be controlled because of poor duct sealing. Also, the ducts should not be
exposed to warm air, or humidity levels may increase.

Humidity Level

Maintain proper humidity levels at 40 to 60% RH. High humidity causes galvanic actions to occur between
some dissimilar metals. This eventually causes a high resistance between connections, leading to equipment
failures. High humidity can also have an adverse affect on some magnetic tapes and paper media.
Low humidity contributes to undesirably high levels of electrostatic charges. This increases the
CAUTION
ESD voltage potential. ESD can cause component damage during servicing operations. Paper
feed problems on high-speed printers are usually encountered in low-humidity environments.
Low humidity levels are often the result of the facility heating system and occur during the cold season. Most
heating systems cause air to have a low humidity level, unless the system has a built-in humidifier.
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Chapter 2